The objective of the current research is to improve treatment for injection opioid users by augmenting buprenorphine pharmacotherapy with an innovative text-messaging strategy to promote relapse prevention skills, reduce HIV-risk behaviors, and improve buprenorphine and HIV treatment regimen adherence. This application is in response to PAS-10-098, Technology Based Adherence Interventions for Substance Abusing Populations With HIV, which encourages multidisciplinary colaboration between social scientists, medical researchers, and technology experts to develop and refine mobile technological instrumentation....as interventions (or part of interventions) that foster adherence to HIV treatment regimens. Consistent with this stated objective of the PAS, the specific aims of this research are 1) To develop and refine, with user feedback, a cognitive behavioral therapy-based text-messaging intervention (TXT-CBT) to augment buprenorphine pharmacotherapy in HIV-infected,injection drug users (IDUs) with opioid dependence; 2) To conduct a pilot randomized clinical trial to assess the feasibility of recruiting and retaining individuals for a lrge scale study and to determine the effect size of TXT-CBT over and above medication management with buprenorphine (MM) on opioid use, HIV medication adherence, buprenorphine adherence, and healthcare outcomes. Both MM and MM+TXT-CBT participants will be assessed at baseline, treatment-end, and 12 weeks post-treatment; and 3) To examine potential mechanisms of action of TXT-CBT, including self-efficacy, affect regulation, and social support. We hypothesize that TXT-CBT delivered in conjunction with MM will produce greater reductions in opioid use and HIV-risk behaviors, and will improve buprenorphine and HIV treatment regimen adherence, relative to MM alone. Further, we expect that MM+TXT-CBT will facilitate greater changes in negative affect, self-efficacy, and social support, and these changes will be associated with substance use outcomes. TXT- CBT incorporates specific substance- and adherence-focused cognitive therapy techniques with a concurrent emphasis on reducing HIV-risk behaviors. By providing support to maximize HIV treatment regimen adherence, coupled with coping skills to address withdrawal symptoms and stress, two important factors in opioid relapse, TXT-CBT may provide a promising, cost-effective, and easily deployable augmenting strategy for the treatment of opioid users who are HIV-infected.